1 Large Box of Jello (any flavor; we used Lime)
2 Cups Sugar
2 Cups Boiling Water,
1 Cup Water
1 Large can of Pineapple Juice (36-40 oz.)
3 Liters Ginger Ale (well chilled)
Plastic Zipper Bags, One Gallon Size

In a large bowl or pot, combine the Jello mix and sugar with the boiling water. Stir to disolve. Add the other cup of water, (room temp is fine). Add the can of pineapple juice and stir. Pour this mixture into the gallon sized plastic zipper bag, seal, and freeze. When you're ready to serve the punch, defrost this mixture for a couple of hours (or microwave it) until it's still frozen, but slushy. Pour the slushy mixture into the punch bowl and then slowly add the 3 liters of chilled ginger ale. Stir to break up any large pieces of the slushy mixture, but don't break them all up. This helps keep the punch nice and cold! There you go! Very simple!
The best part is you can make up the base mixture way ahead of time and just keep it frozen until you're ready to use it. I think this would be easy to convert to almost sugar free by using sugar free jello, splenda or other sweetner, and sugar free ginger ale. The only sugars would be the natural ones in the pineapple juice! Haven't tried that, but just an idea. Enjoy!